Method and apparatus for flexible construction of heat exchanger tanks

ABSTRACT

Heat exchanger header tanks are constructed from a basic set of components. The basic components are castings and simple formed sheet parts. The components are assembled to produce a heat exchanger tank having a desired size and geometry.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of application Ser. No.09/207,886 filed on Dec. 8, 1998 now abandoned entitled METHOD ANDAPPARATUS FOR FLEXIBLE CONSTRUCTION OF HEAT EXCHANGER TANKS and having acommon assignee with the present application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to heat exchangers, and moreparticularly to a method and apparatus for constructing heat exchangertanks that allows for flexibility in size and geometry.

2. Description of the Related Art

A variety of heat exchangers may be used in the cooling system of aninternal combustion engine of a motor vehicle. The cooling systemdisclosed in U.S. Pat. No. 5,570,738 to Christensen includes threedifferent heat exchangers disposed in series flow relationship with oneanother: (1) a condenser for receiving high pressure, superheatedrefrigerant gas from the refrigerant compressor and condensing the gasinto a high pressure liquid for expansion and cooling of the vehiclecab; (2) a charge air cooler (CAC) for cooling the turbocharged engineintake air before the air enters the engine for the combustion process;and (3) a radiator for eliminating waste heat from the internalcombustion engine of the vehicle.

Heat exchangers typically include a central core, and generallyvertically disposed end manifolds or header tanks attached to oppositelateral ends of the core. The core comprises a plurality of tubes andfins, typically disposed in alternating laterally extending rows, withthe tubes communicating with header tanks so as to provide a flowpaththrough the heat exchanger. Ambient cooling air is forced across thetubes and fins during operation of the vehicle resulting in heattransfer from the gas or fluid flowing through the heat exchanger to theambient air stream.

Heat exchangers, such as the radiator, CAC and condenser are surfacearea dependent, in that the temperature reduction achievable in a heatexchanger depends on the available surface area of the design.Therefore, a myriad of different size heat exchangers are necessary toaccommodate the different thermal requirements present in differentapplications. Varying the size of a heat exchanger requires varying thesize of the header tanks. However, conventional heat exchanger tankdesigns require specific tooling for each different design application,as the header tanks are generally cast as a single piece. This isexpensive and results in long lead times for both prototype andproduction parts.

Consequently, a need exists for an improved heat exchanger tank designand for a method of constructing heat exchanger tanks that allows forflexibility in size and geometry.

SUMMARY OF THE INVENTION

The present invention, therefore, provides a method for construction ofheat exchanger header tanks that allows for flexibility in size andgeometry. The header tanks are constructed from a set of basiccomponents that can be assembled as required to match a desired tankdesign for any application. The basic components are cast or formed fromsimple sheet metal parts. The components are assembled to produce a tankof the desired size and geometry. The individual components are thenconnected together, and the final tank assembly is then affixed to theheat exchanger core.

The basic components of the heat exchanger tanks consist of castingswhich form the tank ends, inlet/outlet fittings, and combination tankends with inlet/outlet fittings and structural support attachments, andformed sheet metal center sections which connect the cast portions toform the completed tank.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention will beappreciated as the same become better understood by reference to thefollowing Detailed Description when considered in connection with theaccompanying drawings, wherein:

FIG. 1a is a front elevation view of a heat exchanger according to thepresent invention, having a pair of flexible header tanks;

FIG. 1b is a side elevation view of a heat exchanger according to thepresent invention, having a pair of flexible header tanks;

FIG. 1c is a top elevation view of a heat exchanger according to thepresent invention, having a pair of flexible header tanks;

FIGS. 2a, 2 b, 2 c and 2 d are top, front and side elevation views ofthe flexible header tanks of FIG. 1a;

FIGS. 3a, 3 b and 3 c are multiple sectional views of a tank endcomponent;

FIGS. 4a, 4 b and 4 c are multiple sectional views of a combination tankend component with a fitting;

FIGS. 5a and 5 b are multiple sectional views of a center sectioncomponent;

FIGS. 6a and 6 b are top and front elevation views of an alternateembodiment of the header tank of FIG. 2a;

FIG. 7 is a front elevation view of an assembled radiator moduledemonstrating the attachment structure for the tank supports to themodule frame; and

FIG. 8 is a partial detail view of the comer frame of the module and itsattachment to the tank end component.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, FIGS. 1a-1 c illustrate a heat exchanger,indicated generally at 10, according to the present invention. The heatexchanger 10 includes a central core 12, and first and second headertanks or end manifolds 14, 16, respectively, which are attached toopposite ends of the heat exchanger core 12. The core includes aplurality of laterally extending tubes, which are substantially parallelto one another and which are in fluid flow communication with the headertanks 14, 16 of the heat exchanger. The core 12 also includes aplurality of laterally extending fins having a serpentine, or corrugatedshape which are interdigitated with the tubes.

The heat exchanger 10 further includes an inlet fitting 22, whichcommunicates with the inlet header tank 14 of the heat exchanger and iseffective for receiving a fluid to be cooled during operation of theheat exchanger. Heat exchanger 10 also includes an outlet fitting 24,which communicates with the outlet header tank 16 of the heat exchanger.During operation of the heat exchanger, fluid flows through the inletfitting 22 into the inlet header tank 14, through the tubes 18 where itis cooled by ambient air flowing over the heat exchanger, and into theoutlet header tank 16, where it is discharged through the outlet fitting24.

Referring now to FIGS. 2a-6 b, additional structural features of theheat exchanger tanks 14, 16 are illustrated in greater detail. Theheader tanks 14, 16 are comprised of a common set of basic componentswhich can be assembled as required to match the desired tank design forany application. The basic components are castings and simple formedsheet metal parts. The components are assembled to produce a tank of thedesired size or shape. The individual components are welded together andthe final tank assembly is then welded onto an end of the heat exchangercore.

The basic components of the heat exchanger header tanks consist ofcastings which form the tank ends 26, inlet/outlet fittings 28,combination tank ends with fittings 30, and formed sheet metal centersections 32 which connect the cast portions to form the completed tank.These basic components are combined to provide the required geometry foreach application.

In a presently preferred embodiment, the cast components are cast fromaluminum alloy 319, and the sheet components are formed from 5052-H32aluminum. However, it should be understood that any other suitablematerials or processes may be used for the various components includingdeep draw stamping of sheet metal or comparable processes.

The use of a common set of basic components for construction of heatexchanger tanks provides flexibility of size and geometry of the tankdesign. The sheet metal center sections 32 provide the necessaryflexibility such that the size of the tanks are easily varied asdictated by the thermal requirements of the heat exchanger. Centersections are added, removed, or adjusted between the cast sections asneeded to arrive at the desired tank size and geometry. Additionally,using one set of tooled parts reduces design, tooling and constructioncosts, along with lead time required for both prototype and productionparts.

In the heat exchanger illustrated in FIG. 1a, header tanks 14, 16consist of a tank end 26, a tank end with a fitting 30, and a formedcenter section 32 extending between the tank end 26 and the tank endwith the fitting 30. This configuration of the header tanks, and itscomponents are illustrated in FIGS. 2a-6 b.

As can been seen in FIGS. 3a-3 c, tank end 26 is a cast component havinga generally U-shaped cross section, with a closed end 34, and an openend 36, opposite the closed end. Tank end with a fitting 30 as shown inFIGS. 4a-4 c is a cast component of a similar construction having agenerally U-shaped cross section, with a closed end 38 and an open end40 opposite the closed end. However, as can best be seen in FIGS. 4a-4c, the tank end 30 also includes an inlet/outlet fitting 42 along andextending from a sidewall 44 thereof, in communication with the tank end30. As described above, the fitting 42 permits fluid flow communicationto and from the heat exchanger 10 through the header tanks. Referringnow to FIGS. 5a and 5 b, center section 32 is a formed sheet componenthaving a generally U-shaped cross section, with open ends 46 and 48.

These basic components are assembled to provide the geometry of headers14, 16. Open ends 36 and 40 of the tank ends are preferably welded orbrazed to open ends 46 and 48, respectively, of the center section 32 toarrive at the heat exchanger tank design illustrated in FIGS. 2a-2 d.The size of the tank depends on the size of the individual components.The size of the tank is adjusted as required by the application byadjusting the length of the center section 32.

Referring now to FIGS. 6a and 6 b, an alternate embodiment of a heatexchanger tank 50 according to the present invention is illustrated. Theheader tank 50 consists of a pair of tank ends 26 a, 26 b, aninlet/outlet fitting 28, and a pair of formed center sections 32 a, 32 bextending between the tank ends 26 a, 26 b and the fitting 28. Tank ends26 a, 26 b and center sections 32 a, 32 b are identical in design to thecorresponding components of the embodiment described above. Fitting 28is a cast component having a generally U-shaped cross section with openends 52 and 54. Additionally, fitting 50 includes an inlet/outlet tube56 along, and extending from, a sidewall 58 thereof, to permit fluidflow communication to and from the heat exchanger through the headertanks.

As described above, these basic components are assembled to provide thegeometry of header tank 50. Center section 32 a is welded or brazedbetween tank end 26 a and open end 52 of the fitting 50. Similarly,center section 32 b is welded or brazed between tank end 26 b and theother end 54 of the fitting 50, to arrive at the heat exchanger tank 50design illustrated in FIGS. 6a and 6 b. Again, the size of the tank isadjusted as required by the application by adjusting the length of thecenter sections 32 a, 32 b.

As shown in FIG. 1a generally and in detail in FIGS. 3a, b, c, and 4 a,b, c, the tank end components are formed with integral attachmentfittings 60. The attachment fittings provide integral structuralattachment points for bracketing and other support members to mount andsecure a heat exchanger fabricated using the header tank components ofthe present invention. FIG. 7 shows a complete radiator module assemblyincorporating a heat exchanger as disclosed in FIG. 1a. Corner brackets62 are provided as structural attachments for the heat exchanger to themodule. As best seen in FIG. 8, the corner brackets engage theattachment fittings on the tank end components, receiving flange 64 ofthe fitting in cutout 66 for placement and being secured with bolts 70engaged in treaded bores 68 in the fitting. Incorporation of integralattachment fittings into the end tank end components allows simplicityin structural design of the support structure in addition to thefabrication simplicity of the heat exchanger tanks themselves.

While various embodiments of this invention have been shown anddescribed, it would be apparent to those skilled in the art that manymore modifications are possible without departing from the inventiveconcept herein. For example, the basic components described above may beused in other combinations to arrive at a desired heat exchanger tankgeometry. Such modifications are within the scope and intent of theinvention as defined in the following claims.

What is claimed is:
 1. A method of constructing a heat exchanger headertank comprising the steps of: casting a first common end component and asecond common end component with integral attachment fittings; selectinga length for at least one formed sheet component from a plurality ofpredetermined lengths; cutting the at least one sheet component to theselected length; and connecting the at least one formed sheet componentintermediate the first common end component and the second end componentto form the header tank.
 2. The method as defined in claim 1 wherein thestep of casting includes forming an inlet/outlet fitting on the firstcommon end component.
 3. A method of constructing a heat exchangercomprising the steps of: casting a first common end component and asecond common end component having integral attachment fittings;selecting a length for at least one formed sheet component from aplurality of predetermined lengths; cutting the at least one sheetcomponent to the selected length; and connecting the first and secondcommon end components and the at least one formed sheet componenttogether to form a first header tank; repeating the previous steps toform a second header tank; connecting the first and second header tanksto a heat exchanger core.
 4. A method of constructing a heat exchangerheader tank comprising the steps of: casting a first common endcomponent with a formed inlet/outlet fitting having integral attachmentfittings and a second common end component having integral attachmentfittings; selecting a length for a formed sheet component from aplurality of predetermined lengths; cutting the sheet component to theselected length; and welding the formed sheet component intermediate thefirst common end component and the second end component to form theheader tank.